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Spokane River Dams


Post Falls Hydroelectric Development

The Post Falls Hydroelectric Development is located in northern Idaho, nine miles downstream of Coeur d'Alene Lake. It was constructed where the Spokane River branches into three separate channels. The development includes a dam in each channel. Besides producing electricity, the development affects water levels in Lake Coeur d'Alene and parts of the Coeur d’Alene, St. Joe andPost Falls Hydroelectric Development St. Maries rivers during the summer recreation season.

The middle channel dam includes the powerhouse, which contains six generating units. Five were operational by 1908; the sixth was added in 1980.

The City of Post Falls operates two public parks surrounding the development. Both parks were cooperatively developed, primarily with Avista-donated land and funding. Adjacent to the North Channel Dam lies Falls Park. Dedicated in June 1993, the park offers paved trails, a viewpoint with ADA-accessible ramp, playground equipment, a picnic area, a fishing pond for children, and a series of interpretive signs describing the early history of the dams and surrounding area. Adjoining the South Channel is Q'emiln Park, which contains picnic shelters, swimming and boat launching facilities, and an extensive system of hiking trails.

Licensed Generating Capacity: 15 Megawatts
Dam Height: Up to 64 Feet
Generating Units: 6

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Upper Falls Hydroelectric Development

Completed in 1922, the Upper Falls Hydroelectric Development was instrumental in meeting the growing demands of Spokane's industrial and residential developments. Upper Falls also helped power Spokane’s early electric streetcar system. Upper Falls Hydroelectric Development

Upper Falls is constructed on two separate river channels in the heart of downtown Spokane. The last development we built on the Spokane River includes both a diversion dam and a powerhouse.

The diversion dam (also known as the Division Street Control Works) is located on the river's main channel. It diverts water through the south river channel, past the Spokane Convention Center and Red Wagon, and into the development's intake structure. Here, via an eighteen-foot diameter underground pipe called a penstock, the water is directed downhill to the powerhouse where it is used to generate electricity. This water is then returned, unaffected, back into the main river channel.

The facility quietly produces electricity in harmony with the serene beauty of surrounding Riverfront Park, site of the 1974 World’s Fair. Offering visitors beautiful, year-round scenic views of Spokane’s “Upper Falls”, the park contains numerous recreational opportunities including open-air concerts, an IMAX Theatre, and the fully-functioning antique Looff Carrousel. Visitors can enjoy a self-guided tour of Riverfront Park by following a series of interpretive signs located throughout the park.

Upper Falls HED Map 

Licensed Generating Capacity: 10 Megawatts
Dam Height: 35 Feet
Generating Units: 1

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Monroe Street Hydroelectric Development

We have been producing power from our Monroe Street Hydroelectric Development since 1890, longer than any other hydroelectric facility in the state of Washington. The dam, located in the core of downtown Spokane was constructed at a natural waterfall, Spokane’s “Lower Falls.” It helped the town of Spokane Falls move from candles and oil lamps to incandescent lighting.Monroe Street Hydroelectric Development

The dam was rebuilt just prior to the 1974 World’s Fair, held in Spokane, and a new underground powerhouse was completed in 1992. As part of the new construction, five vintage 1900-era turbines and generators were replaced with one state-of-the-art generating unit able to produce twice the electrical power while using the same amount of water flow. We donated one of the original turbines to the Henry Ford Museum in Dearborn, Michigan.

Just downstream of the city’s Riverfront Park, the spectacular Monroe Street spillway and “Lower Falls” can be seen from several different viewing areas, including the seasonal park gondola ride. The adjacent Huntington Park, owned and maintained by Avista for public use, offers opportunities for viewing the Lower Falls and contains a fenced promenade near the falls.

Monroe Street HED Map

Licensed Generating Capacity: 15 Megawatts
Dam Height: 24 Feet
Generating Units: 1

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Nine Mile Hydroelectric Development

Completed in 1908, Nine Mile Hydroelectric Development was designed by the world-famous Sanderson & Porter engineering firm of New York.  Built during the peak years of Spokane’s “Street Car Era,” the development was originally constructed to supply power to the 130-mile-long Spokane & Inland Empire Railroad Company’s electric railway system.Nine Mile Hydroelectric Development

The development was purchased in 1925 by Avista, and later a series of brick cottages were built northwest of the dam to provide housing for personnel. Today, both the plant and the cottages are listed on the National Register of Historic Places.

Renovations include a new control room, replacement of two of the four vintage turbines, a new automated spillway, and restoration of several of the historic cottages. Six of the cottages have been leased at no cost to Riverside State Park for use by park rangers.  Future renovations include replacing the two remaining vintage turbines and restoration work at the powerhouse and one of the cottages, which will be used as an administrative facility.

During spring runoff, a spectacular view of the Nine Mile spillway can be seen from the Charles Road Bridge and the new scenic overlook, located just north of the dam. Consisting of more than 10,000 acres, Riverside State Park surrounds the Nine Mile development and provides camping, boating, hiking, bicycling, and equestrian trail-riding opportunities. Over the years, we have donated more than 500 acres to Riverside State Park.

Nine Mile HED Map

Licensed Generating Capacity: 26 Megawatts
Dam Height: 58 Feet
Generating Units: 4

Watch a time-lapse video of how Avista replaced two 1908 Turbine Generators at the Nine Mile Hydroelectric Project

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Long Lake Hydroelectric Development

Billed as the “world’s highest dam” when it was completed in 1915, the Long Lake Hydroelectric Development is listed in the National Register of Historic Places. It took more than 500 workers to construct the dam, which was built in a spot where the Spokane River makes a complete horseshoe bend. A large encampment was established at the project site during construction, complete with all the amenities of an early 1900s town.Long Lake Hydroelectric Development

The development, with its four highly visible, exposed penstocks, can be viewed from a scenic overlook on the north side of the river. This paved, ADA-accessible viewpoint directly overlooks the Long Lake spillway. Nesting ospreys can be seen nearby. There's also a public day-use and picnic area with playground equipment on the south bank of the river downstream of the powerhouse.

Long Lake Dam's 24-mile-long reservoir, Lake Spokane, provides numerous fishing, boating, camping, and swimming opportunities. Part of the lake is adjacent to the 10,000 acre Riverside State Park, which includes more than 500 acres of land donated by Avista.  Riverside State Park personnel also manages Avista's property for public recreation.

Long Lake HED Map 

Licensed Generating Capacity: 71 Megawatts
Dam Height: 213 Feet
Generating Units: 4

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